1. Field of the Invention
This invention relates to an improved air return bulkhead for refrigeration vehicles, including a unitary body member formed from synthetic plastic material and having top, side, and apertured bottom walls that cooperate with a vertical first wall and with an internal surface of the front wall of the refrigeration vehicle to define a plenum chamber, characterized by the provision of support means on the internal surface of the apertured bottom wall in downwardly spaced relation to the bottom edge of the front wall, said support means being arranged to engage the vehicle front wall to which the bulkhead is fastened.
2. Brief Description of the Prior Art
Air return bulkheads are known in the patented prior art, as evidenced by the Severson U.S. Pat. No. 4,399,737, Henning, et al., U.S. Pat. Nos. 5,769,704 and 5,947,812, and Onken U.S. Pat. Nos. 5,807,046 and 5,993,310, among others. These air return bulkheads are generally formed from fiberglass or a synthetic plastic material and are fastened to the inner surface of the front wall of a refrigeration vehicle having a refrigeration unit mounted in an opening contained in the upper portion of the front wall. The air return bulkheads normally protect and cooperate with the front wall on which they are mounted to define a plenum chamber into which air is introduced via apertures contained in the bottom walls of the bulkheads. The air—which is filtered by the apertures to remove the waste particles present in the container chamber—is directed upwardly toward the air inlet of the refrigeration unit. It is conventional in the art to provide such bulkheads at their lower ends a plurality of integral vertically-arranged horizontally-spaced forwardly-protruding pallet stops that prevent the pallets and the loads carried thereby from damaging the bulkheads and from blocking the air inlet apertures formed in the bottom walls of the air return bulkheads.
As shown by the Morgan U.S. Pat. No. 4,495,857, it has similarly been proposed to provide a labyrinth ventilator for marine cargo containers that is formed as a unitary body from a synthetic plastic material, which ventilator includes a plenum chamber that is in communication with inlet openings that supply ventilating air to the container. In this Morgan patent, the bottom wall contains a plurality of apertures for admitting air into the plenum chamber, and support means are provided for engaging the associated container wall to support the vertical front wall of the ventilator. Similar support means are formed as recesses or flutes contained in the planar front wall of the air return bulkheads of the aforementioned Onken patents.
The concept of cutting an article to size along predetermined lines of cut is disclosed in the Belk U.S. Pat. No. 2,909,234, Cantieri U.S. Pat. No. 4,279,439, and the Onken patents, and the provision of cutting guide grooves per se is disclosed in the Graves, et al., U.S. Pat. No. 4,539,239, and Horiki, et al., U.S. Pat. No. 5,164,238. Finally, it is well known in the art to nest or stack a plurality molded articles for economic and efficient storage and/or transport, as shown by the patents to Reynolds, et al., Reissue No. 33,200, Queen, et al., U.S. Pat. No. 4,801,169, Ryan U.S. Pat. No. 5,167,433, and the Onken patents. To this end, the cooperating nesting surfaces of the articles being stacked have an angle of nesting or taper on the order of 2° or more.
The present invention was developed to provide an improved air return bulkhead of streamlined design that is more economically and efficiently produced, that effectively supports the apertured bottom wall of the bulkhead, and that avoids the provision of the unsightly forwardly protruding pallet stops.